Hydrogen Bond Promoted Carbonylative Lactonization of Alkenes

The formation of complexed molecules through intramolecular hydrogen bond to facilitate chemical reactions is an applicable strategy in organic synthesis. Among the lactones, γ-butyrolactones is a class of biologically active and important structures. In this work, a series of γ-butyrolactones were synthesised in a green and efficient manner by carbonylation of alkenes. This reaction is also applicable to the synthesis of lactones containing natural product modules. The formation of an intramolecular hydrogen bond between the pyridine group and the hydroxyl group is imperative for enhancing the nucleophilicity of the large steric alcohol, which are challenge to lactonize. The existence of intramolecular hydrogen bond was proven with the aid of FT-IR and NMR characterisation.